CPU Clock Speed Fluctuating – 4 Reasons Why

Noticing that your CPU clock speed keeps going up and down can be quite frustrating, it may seem like abnormal behaviour which needs to be fixed.

However, the CPU clock speed depends on many variables such as CPU load, Temperature, Voltages, and overclocks, so many things can be at play.

But in general, when the CPU’s clock speed is fluctuating, there’s usually nothing to worry about, clock speeds are dynamic, and are subject to change based on multiple variables.

What Is The CPU Clock Speed?


The CPU’s clock speed is one of the most important metrics to follow when gauging how well the CPU can perform.

Clock speed refers to how many times the CPU cycles per second, so if the clock speed is 5GHz, that means the CPU will cycle 5 billion times per seconds.

The clock speed plays a huge role especially in gaming computers, so when it fluctuates, it can have a huge impact on the FPS.

Also Read: What Is A Good CPU Clock Speed?

1. Fluctuates Based On Load

The clock speed will fluctuate based on load, and the clock speed will usually ramp up when the load increases.

So when you’re gaming, or performing CPU intensive tasks, the CPU clock speed is likely to increase to whatever speed is necessary for the task at hand.

When your computer is idle and not performing any important tasks, the CPU has no reason to run at max speed, this is ideal to save power and keep temperatures low.

For Intel, this feature is called “Speedstep“, and the technical name is called “Dynamic Frequency Scaling”, and the goal is to allow the CPU to instantly provide necessary performance for the task running.

2. Background Tasks

Just because you’re not doing anything on your computer, it doesn’t mean the computer is actually not doing anything.

There are usually operating systems, and other software background tasks running which can cause the CPU clock speed to fluctuate.


In “Task Manager” you can usually find the number of background processes running, these are the applications constantly running regardless if your computer is idle or not.

Some background processes are necessary for the system to run, some can be terminated by the user’s command.

Solution: Stripping Background Tasks Upon Start-up

Within the Task manager, you as the user have control over what applications automatically start when the system boots.

It’s recommended to disable applications that you don’t really use, or have a huge start-up impact, to do this it’s pretty simple.

  2. Select Task Manager & head over to “Startup”
  3. Within the startup section, you can pick and choose what applications to disable
  4. Disable all applications with a high start-up impact except for necessary applications like antiviruses.

Once you’ve disabled some background tasks, restart the system and check whether the CPU clock speed keeps fluctuating.

If the background tasks were causing the CPU to fluctuate, then you should notice a more consistent clock speed after disabling the applications.

3. CPU Temperature And Voltages / Thermal Throttling

When your processor is under load, the first thing that will happen is the CPU will “boost” or automatically boost its clock speed.

This will naturally cause the CPU temperature to rise, and heat is pretty dangerous as it can cause many CPU components to fail.

This is why there are safety measures such as Thermal Throttling which will occur once your processor reaches a certain temp.


Thermal throttling is the act of reducing performance in an attempt to reduce the temperature of the processor.

The reduction of performance usually comes in the form of reducing the clock speed, this is why it seems like your CPU clock speed is fluctuating.

Thermal throttling is completely normal especially if your computer has bad cooling, so if you have a good cooling solution, you can reduce the effects of thermal throttling.

Thermal Throttling is usually a product of many things such as having a bad airflow setup, poor/faulty CPU cooler, or a PC case with clogged up vents.

To reduce thermal throttling, try reducing dust within the case by using compressed air, improving the airflow setup, and replacing the air cooler.

Reducing the voltage of the CPU is a great way at keeping temperatures low, in many cases, this can solve thermal throttling/fluctuating clock speeds.

4. Malware

Malware is malicious software that abuses your computer’s resources for personal gain which can be the cause for your CPU clock speed constantly fluctuating.

Malware will use your CPUs resources for crypto mining, stealing data, and many other malicious activities, this is why it’s important to ensure safety when using your computer.


There are usually two effective ways to handle malware, the first way is to use a credible anti-malware software such as “MalwareBytes”.

Complete a full system scan to get the best results, it should find malicious software on your device, and removing it will undoubtedly make your system faster.

The second method of removing malware is to reset/wipe your device, this is more extreme, but it’s great at making sure no malware remains on your system.

So, if you’re certain that your system has malware, employ one of these methods to give your system a fresh start.


In conclusion, your CPU’s clock speed will fluctuate for many reasons, but most of the time, the fluctuation is completely normal.

However, the fluctuation can be a symptom of something malicious such as malware, in this case, you can use antimalware software, or wipe your system.

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